Prior art which may provide useful background information to this technical field can e.g. be found by the technical specification TS 36.816 (current version: 1.0.1) of the 3GPP.
The following meanings for the abbreviations used in this specification apply:
3GPP 3rd Generation Partnership Project
A-LTE Advanced LTE
BCCH Broadcast Control Channel
BS Base Station
BT Bluetooth
CDIS Coexistence Discovery and Information Server
C carrier
CC Carrier Component
CE Coexistence Enabler
CM Co-existence Manager
CMRS Commercial Mobile Radio Service
DCI Downlink Control Information
DL Downlink
DRX Discontinuous Reception
EDGE Enhanced Data Rates for GSM Evolution
eNB evolved Node B
FCC Federal Communications Commission
FDD Frequency Domain Duplexing
GERAN GSM EDGE Radio Access Network
GNSS Global Navigation Satellite System
GSM Global System for Mobile Communications
HARQ Hybrid Automatic Request
IEEE Institute of Electrical and Electronics Engineers
ISM Industrial Scientific Medical
LTE Long Term Evolution
MAC Media Access Control
PCell Primary Cell
PDCCH Physical Downlink Control Channel
PLMRS Private Land Mobile Radio Service
PRB Physical Resource Block
RRC Radio Resource Control
SCell Secondary Cell
TDD Time Domain Duplexing
TDM Time Domain Multiplexing
TVBD TV Band Devices
TVWS Television White Space
UE User Equipment
UL Uplink
UMA Unlicenced Mobile Access
UMTS Universal Mobile Telecommunications System
USB Universal Serial Bus
UTRAN UMTS Terrestrial Radio Access Network
WiFi Wireless Fidelity
WMTS Wireless Medical Telemetry Service
WRAN Wireless Regional Area Network
The deployment of LTE wireless nodes such as macro/micro eNBs, pico eNBs, and Home eNBs in heterogeneous networks in the same spectrum create new interference challenges. The study of these challenges and potential solutions are currently part of an agreed Release 10 Working Item in 3GPP (see e.g. RP-100383, “New Work Item Proposal: Enhanced ICIC for non-CA based deployments of heterogeneous networks for LTE”, RAN#47, March 2010). It shall Include consideration of Rel8/9 techniques and ensure backward compatibility for Rel8/9 terminals as well as minimize physical layer air interface impact.
To prevent that licensed spectrum scarcity becomes a bottleneck for such heterogeneous networks with ever increasing levels of interference, LTE systems could also be deployed in the TV White Space (TVWS) bands with the licensed band resources being used during the initial setup. The potential use of TV white spaces has been investigated widely in the recent years, due to their available large bandwidths at suitable frequencies for different radio applications.
In the US, the Federal Communications Commission (FCC) have regulated licensed or license-exempt TV bands for the secondary-system applications (i.e. cellular, WiFi, WiMax)) on TV Band Devices (TVBD).
At present, the FCC defines two concepts for the help of find available channels, namely a TV bands database and the geo-location capability. A TV band database that maintains records of all authorized services in the TV frequency bands is capable of determining the available channels as a specific geographic location and provides lists of available channels to any TVBD that has been certified under the FCC's equipment authorization procedures. The geo-location capability is defined for some of the TVBD. A TVBD with such capability should be able to determine its geographic coordinates within a certain level of accuracy (±50 m). This capability is used with a TV bands database to determine the availability of TV channels at the specific location of a TVBD.
The following table gives the available TVWS bands in the US (see e.g. FCC 10-174, “SECOND MEMORANDUM OPINION AND ORDER”, Sep. 23, 2010). Each TV channel has 6 MHz bandwidth and would typically be sufficient for any of the wireless communications.
Frequency Range(correspond TV channelnumbers)Center FrequencyAvailable bandwidth 54-60 MHz (2) 57 MHz 6 MHz 76-88 MHz (5, 6) 82 MHz12 MHz174-216 MHz (7-13)195 MHz42 MHz470-608 MHz (14-36)539 MHz138 MHz 614-698 MHz (38-51)656 MHz84 MHz
Most of the current applications in the TV bands are considered as primary applications, including;                TV services: including analog services and digital services. They can occupy any VHF and UHF channel (2 to 51), except channel No. 37.        The Wireless Medical Telemetry Service (WMTS) and radio astronomy: using TV channel 37 (608-614 MHz). This channel cannot be used for any other services. Further, no TVBD is allowed to operate at any band within 2.4 km of the facilities using radio astronomy services to avoid causing interference.        The Private Land Mobile Radio Service (PLMRS) and the Commercial Mobile Radio Service (CMRS): They can use 1 to 3 TV channels in the range of channels 14-20.        Some regional based services: Such as the Offshore Radiotelephone Service which uses channels 15-17 in certain regions along the Gulf of Mexico, and the inter-Island communications in Hawaii, which use channel 17.        
In addition, there are also some existing secondary systems such as wireless microphone (channel 7-46) and unlicensed remote control devices (above channel 4).
To help the TVBDs find available channels, the FCC has introduced the following:                TVWS database available online by the TVBDs (typically via internet connection) that indicate the available channels at a specific geographic location.        TVBD geo-location capability using GPS or other adequate positioning methods within required accuracy. This is used with the TVWS database to check the available TV channels at a TVBD's location.        
Such mechanisms aim to set up TVBD connections in TVWS channels when not used by the primary systems, but do not apply to secondary systems. Cellular network operators may have cellular database showing their coverage accurately, but are unlikely to allow competitors to use them. On the other hand, a WiFi database including home WiFi networks is not likely.
There is a need to find a solution that allows to on the one hand re-use existing mechanisms to check TVWS channels which are not used by primary systems (i.e. TVWS database, TVBD geo-location), while on the other hand determine whether available TVWS channels are also free from other secondary-system interference.
IEEE 802.22 is a standard for Wireless Regional Area Network (WRAN) using white spaces in the TV frequency spectrum (see e.g. C. Stevenson, et. al, “IEEE 802.22: The first cognitive radio wireless regional area network standard,” IEEE Communication, January 2009). The IEEE 802.22 WRAN standard aims to using cognitive radio techniques to allow sharing of geographically unused spectrum allocated to the Television Broadcast Service, on a non-interfering basis, in order to bring broadband access to hard-to-reach, low population density areas, typical of rural environments. IEEE 802.22 introduces a general co-existence beacon which is transmitted during so-called co-existence windows at the end of some frames by the base station (BS) and/or some designated device. These co-existence beacons are monitored by the BSs and other devices from same and different cells on the same channel or different channel for the future channel switching purposes.
IEEE 802.19.1 proposes co-existence mechanisms for heterogeneous networks in TVWS (see e.g. Developing a Standard for TV White Space Coexistence: Technical Challenges and Solution Approaches, Tuncer Baykas, NICT, Mark Cummings, Envia, Hyunduk Kang, ETRI, Mika Kasslin, Nokia, Joe Kwak, InterDigital, Richard Paine, Alex Reznik, InterDigital, Rashid Saeed, TMRND, and Stephen J. Shellhammer, Qualcomm, http://www.ieee802.org/19/arc/stds-802-19list/docrnXZz7qdyI.doc). A common control block enables the coexistence between different secondary systems, which can exchange the necessary information and determine how to share the resources. A Coexistence Manager (CM) is used for discovery of other CMs, making coexistence decisions, support exchange of information required for coexistence among CMs, and assist network operators in management related to TVWS coexistence. The Coexistence Enabler (CE) requests co-existence information from TVBD network or device, translates reconfiguration requests/commands and control information received from the Coexistence Manager (CM) into TVBD-specific reconfiguration requests/commands and sends them to the TVBD network or device; the Coexistence Discovery and Information Server (CDIS) supports discovery of CMs (facilitates the opening of interfaces between CMs), and to collect, aggregate, and provide information facilitating coexistence. The general mechanisms described in 802.22 and 802.19.1 could to some extent apply to cellular TVBDs, but specific ways for the setting up of LTE cellular systems (i.e. configuration of DL and UL carriers on TVWS band for LTE communications between the eNBs and LTE TVBDs) are not covered in the IEEE standardization.
In the specification TR 36.816, Release 10, v1.0.1, “Study on signalling and procedure for interference avoidance for in-device coexistence”, mechanisms to avoid coexistence interference between collocated radio transceivers in devices equipped with LTE, WiFi, BT transceivers and GNSS receivers are considered. The level of interference depends on whether the LTE and ISM bands are close and on assumptions on filtering, antenna isolation and so on. Interference avoidance based on internal coordination between the ISM and LTE radio technologies within the same UE is one way proposed (possibly coordinated with the network, which decides how to avoid the interference). Other ways based on LTE network-controlled UE-assisted solutions involve (i) Frequency Domain Multiplexing by moving the LTE signal away from the ISM band or moving the WiFi signal away from the LTE band; (ii) Time Domain Multiplexing of WiFi and LTE signals via DRX-based TDM patterns or HARQ process reservation; (iii) LTE Power Control or ISM Power Control. Interference measurements in the ISM band and the LTE band may be needed depending on the solution type. The solutions require dedicated signaling—e.g. DRX-based TDM patterns can be configured for a specific device to avoid in-device interference.